Preparation of tertiary butyl alcohol by catalytic decomposition of tertiary butyl hydroperoxide

Abstract: A method for preparing tertiary butyl alcohol wherein a feedstock comprising a solution of tertiary butyl hydroperoxide in a cosolvent mixture of tertiary butyl alcohol with isobutane is charged to a hydroperoxide decomposition reaction zone containing a catalytically effective amount of a hydroperoxide decomposition catalyst and is brought into contact with the catalyst in liquid phase with agitation under hydroperoxide decomposition reaction conditions to convert the tertiary butyl hydroperoxide to decomposition products, principally tertiary butyl alcohol.

Description: This invention relates to a method for the preparation of tertiary butyl alcohol (TBA) by the catalytic decomposition of tertiary butyl hydroperoxide (TBHP). More particularly, this invention relates to a method wherein a tertiary butyl hydroperoxide charge stock comprising a solution of tertiary butyl hydroperoxide dissolved in a cosolvent mixture of isobutane and tertiary butyl alcohol is brought into contact with a hydroperoxide decomposition catalyst in a reaction zone to convert the tertiary butyl hydroperoxide to peroxide decomposition products, principally tertiary butyl alcohol. It is known to react isobutane with oxygen, either thermally or catalytically, to form a peroxidation reaction product wherein the principal peroxide that is formed is tertiary butyl hydroperoxide. It is also known to thermally or catalytically decompose the tertiary butyl hydroperoxide in a peroxide decomposition zone to form tertiary butyl alcohol. Normally, the unreacted isobutane is removed from the peroxidation reaction product so that the feedstock for the hydroperoxide decomposition zone is a debutanized peroxidation reaction product. In the text entitled "Organic Peroxides" edited by Daniel Swern (Wiley Interscience, a Division of John Wiley & Sons, New York), in Vol. II on page 157 it is stated that the metal-ion-catalyzed decomposition of primary hydroperoxides yields mainly alcohols, aldehydes and carboxylic acids, citing as an example the decomposition of hydroxymethyl hydroperoxide with aqueous ferrous sulfate to provide formaldehyde, formic acid and water. US-A-3,505,360 discloses a method wherein an alkenyl hydroperoxide is decomposed in the presence of a catalyst based on a compound of a Group IV-A, V-A or VI-A metal. US-A-4,508,923 discloses the use of a catalyst system comprising ruthenium and chromium for decomposing organic hydroperoxides. The use of a cobalt borate catalyst for the decomposition of hydroperoxides is disclosed in US-A-4,547,598. US-A-4,551,553 is directed to a process for the formation of alcohols such as tertiary butyl alcohol by the catalytic decomposition of an organic hydroperoxide such as tertiary butyl hydroperoxide using a binary catalyst composed of a mixture of a ruthenium compound with a chromium compound. It is stated that the use of the binary catalyst eliminates the need for stabilizing ligands. Sanderson et al. disclose the use of a variety of catalysts for the decomposition of tertiary butyl hydroperoxide in a series of U. S. patents, including a catalyst composed of unsupported nickel, copper, chromia and iron (U. S. Patent No. 4,704,482), a catalyst composed of iron, copper, chromia and cobalt (U. S. Patent No. 4,705,903), a catalyst composed of a base treated hydrogenation catalyst from groups VIB or VIIIB of the Periodic Table (U. S. Patent No. 4,742,179), a catalyst consisting essentially of nickel, copper, chromium and barium (U. S. Patent No. 4,873,380), a catalyst composed of a metal phthalocyanine promoted with a rhenium compound (U. S. Patent No. 4,910,349), a catalyst composed of a base promoted metal phthalocyanine compound, (U. S. Patent No. 4,912,269), a catalyst composed of a soluble ruthenium compound promoted with a bidentate ligand (U. S. Patent No. 4,912,033), a catalyst composed of a metal porphine such as iron (III) or manganese (III) promoted with an alkyl thiol or an amine, a catalyst composed of an imidazole promoted metal phthalocyanine compound (U. S. Patent No. 4,912,266), (U. S. Patent No. 4,922,034), a catalyst composed of a metal phthalocyanine promoted with a thiol and a free radical inhibitor (U. S. Patent No. 4,922,035), a catalyst composed of a borate promoted metal phthalocyanine (U. S. Patent No. 4,922,036), or a catalyst composed of a soluble ruthenium compound and an iron compound such as an acetate, a borate, a bromide, a chloride, a 1,3-propanedionate, a 2-ethylhexanoate, an iodide, a nitrate, a 2,4-pentanedionate, a perchlorate or a sulfate (U. S. Patent No. 5,025,113). As stated, when isobutane is reacted with molecular oxygen, the principal products of the reaction are tertiary butyl alcohol and tertiary butyl hydroperoxide. However, minor amounts of other contaminants are also formed. A minor amount of water will be formed, which will normally amount to 0.5 to 1 wt.% of the reactor effluent. The amount of byproduct water that is produced is a function of the severity of the reaction conditions employed and will tend to increase as the severity of the reaction conditions is increased. As indicated, tertiary butyl hydroperoxide is useful as a raw material for the manufacture of tertiary butyl alcohol. The tertiary butyl alcohol can be formed by catalytic decomposition of the tertiary butyl hydroperoxide. EP-A-0336480 describes a process for preparing tertiary butanol. Tertiary butanol (TBA) is produced in the liquid phase by catalytic oxidation of isobutane with molecular oxygen. This gives a crude product containing TBA and, inter alia, tertiary butyl hydroperoxide (TBHP). TBA is isolated from the crude product by fractional distillation. The reaction is carried out using a catalyst which is a transition metal compound containing nitrogen-containing ligands or else is a polymeric phthalocyanine. The catalyst is virtually insoluble in the reaction mixture. The crude product is preferably prepared at temperatures of from 100 to 135°C and at a pressure in the range from 5 to 50 bar. DE-A-3248465 describes a further process for preparing tertiary butanol. The disclosure relates to a process which involves the oxidation of isobutane in the liquid phase and decomposition of the hydroperoxide formed in the reaction, according to which the oxidation of the isobutane is carried out with addition of catalysts and at conversions of from 48 to 90%, and the hydroperoxide formed is subsequently treated under hydrogenating conditions. In accordance with the present invention, a tertiary butyl hydroperoxide charge stock is used which comprises a solution of tertiary butyl hydroperoxide in a cosolvent mixture of isobutane with tertiary butyl alcohol. A feedstock for the present invention is suitably one formed by the oxidation of isobutane with molecular oxygen to provide an oxidation reaction product containing a solution of tertiary butyl hydroperoxide in tertiary butyl alcohol and unreacted isobutane. The tertiary butyl hydroperoxide charge stock will suitably comprise from 5 to 30 wt.% of tertiary butyl hydroperoxide and, correspondingly, 95 to 70 wt.% of cosolvent. The cosolvent will suitably comprise from 50 to 80 wt.% of isobutane and, correspondingly, from 50 to 20 wt.% of tertiary butyl alcohol. If the tertiary butyl hydroperoxide charge stock is an isobutane peroxidation reaction product that contains more than 30 wt.% of tertiary butyl hydroperoxide, tertiary butyl alcohol may be added in amount sufficient to provide for the desired concentration of tertiary butyl hydroperoxide in the cosolvent mixture of isobutane and tertiary butyl alcohol. The tertiary butyl hydroperoxide charge stock is charged to a catalytic hydroperoxide decomposition zone wherein the tertiary butyl hydroperoxide is decomposed in the presence of a suitable peroxide decomposition catalyst such as a palladium catalyst. The tertiary butyl alcohol will not be the only decomposition product that is formed. Minor amounts of other oxygen-containing materials such as those listed above will also be formed. The tertiary butyl alcohol that is recovered from the decomposition reaction mixture will be contaminated with the oxygenated impurities. The Catalyst System The catalyst system comprises an alumina-supported palladium/gold catalyst, and most preferably consists essentially of alumina having deposited thereon 0.2 wt.% of palladium and 0.08 wt.% of gold. Catalytic Decomposition of Tertiary Butyl Hydroperoxide The process of the present invention may be conducted batchwise in kettles or by continuously passing the reactants through a tubular reactor. The catalytic decomposition of the tertiary butyl hydroperoxide is preferably conducted at a temperature within the range of 25° to 250°C. and, more preferably, at a temperature within the range of 40 to 150°C. The reaction is preferably conducted at a pressure sufficient to keep the products and reactants in liquid phase. Pressures, including autogenous pressure of 0.1 to 69 MPa (0 to 10,000 psig), preferably 0.1 to 7.0 MPa (0 to 1,000 psig) may be used, if desired. Flow rates of the charge solution to the reaction zone should be adjusted in order to provide an appropriate contact time within the reactor. In a batch process, the holding time may suitably be from 0.5 to 10 hours, and more preferably 1 to 3 hours. In a continuous process, the space velocity is suitably within the range of 0.5 to 2 volumes of tertiary butyl hydroperoxide charge stock per volume of pelleted catalyst per hour. In accordance with a preferred embodiment of the present invention, isobutane is reacted with oxygen in an oxidation zone under oxidation reaction conditions including a temperature of 135 to 155°C., a pressure of 2.1 to 5.6 MPa (300 to 800 psig), and a holding time of 2 to 6 hours to provide an initial oxidation reaction product comprising unreacted isobutane, tertiary butyl hydroperoxide, tertiary butyl alcohol, and oxygen-containing by-products. The initial oxidation reaction product is then used as the tertiary butyl hydroperoxide charge stock of the present invention. If the concentration of tertiary butyl hydroperoxide in the tertiary butyl hydroperoxide charge stock is more than about 30 wt.% of the initial oxidation reaction product, the initial oxidation reaction product can be diluted with an amount of tertiary butyl alcohol sufficient to lower the concentration of the tertiary butyl hydroperoxide to a desired percentage, to provide, for example, a tertiary butyl hydroperoxide charge stock containing from 5 to 25 wt.% of tertiary butyl hydroperoxide. The remainder of the tertiary butyl hydroperoxide charge stock will comprise a mixture of isobutane and tertiary butyl alcohol, such as a mixture comprising about 20 to 50 wt.% of tertiary butyl alcohol with, correspondingly, about 80 to 50 wt.% of isobutane. The tertiary butyl hydroperoxide charge stock is then charged to a catalytic hydroperoxide decomposition zone where it is brought into contact with a suitable hydroperoxide decomposition catalyst to convert the tertiary butyl hydroperoxide to tertiary butyl alcohol with high yield and selectivity. When the process of the present invention is practiced in a continuous manner by continuously charging the tertiary butyl hydroperoxide charge stock to a reactor containing a fixed bed of pelleted hydroperoxide decomposition catalyst, the space velocity is suitably in the range of 0.5 to 3 volumes of tertiary butyl hydroperoxide charge stock per volume of catalyst per hour. Preferably, the space velocity is within the range of 0.5 to 1 volume of tertiary butyl hydroperoxide charge stock per volume of catalyst per hour. The reaction product from the tertiary butyl hydroperoxide decomposition step may then be fractionated in any suitable manner, such as by distillation to recover the tertiary butyl alcohol. EXAMPLES The invention will be further illustrated by the following non-limiting examples. Reactor The reactor was a stainless steel tube (13mm x 736mm) which was electrically heated. Liquid feed was pumped into the bottom of the reactor. Pressure regulation was with a Skinner Uni-Flow® valve and a Foxboro® controller. The liquid feed was pumped with a Ruska® dual drive pump. Samples were collected at each space velocity and temperature using a 150 cc stainless steel bomb. The bomb was fitted with a pressure gage and rupture disk. Isobutane peroxidation reactor effluent was obtained from a pilot plant peroxidation reactor. Analysis of the reactor effluent was by Gas Chromatography. Details are given in the following tables. CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL RUN A 1 2 3 4 Catalyst .2% Pd, .08% Au on Al 2 O 3 Catalyst (cc) 100 100 100 100 Pressure (MPa) 2.1 2.1 2.1 2.1 Feed Rate (cc/Hr.) 50 50 50 50 Temperature (°C) 40 60 80 100 Time on Stream (Hr) 4 4 4 4 Space Vel. (cc/cc) 0.5 0.5 0.5 0.5 TBHP Conversion (mol.%) 56.3 82.7 92.9 99.6 IB Conversion (mol.%) 13.1 0.0 13.4 3.5 Sel. Acetone (mol.%) 0.2 2.3 6.9 6.8 Sel. Methanol (mol.%) 0.0 0.2 0.7 0.5 Sel. TBA (mol.%) 99.8 91.7 86.9 89.5 Sel. DTBP (mol.%) 0.0 6.1 6.1 3.7 Composition C3= 0.019 0.020 0.023 0.029 0.029 Isobutane 57.704 50.167 58.187 49.961 55.712 MEOH/MF 0.101 0.089 0.112 0.142 0.136 Acetone 1.128 1.139 1.346 1.875 1.915 TBA 21.338 38.448 34.791 43.904 40.044 DTBP 0.681 0.404 1.418 1.518 1.220 TBHP 18.084 7.894 3.126 1.291 0.079 If one compares Tables I-IV with Tables V-VII, it is clear that the selectivities to TBA are higher in the presence of isobutane. This is at least partially due to the conversion of a portion of the isobutane to TBA. CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL RUN A 5 6 7 8 Catalyst .2% Pd, .08% Au on Al 2 O 3 Catalyst (cc) 100 100 100 100 Pressure (MPa) 2.1 2.1 2.1 2.1 Feed Rate (cc/Hr.) 50 50 50 50 Temperature (°C) 40 60 80 100 Time on Stream (Hr) 4 4 4 4 Space Vel. (cc/cc) 0.5 0.5 0.5 0.5 TBHP Conversion (mol.%) 21.7 62.9 87.8 96.5 IB Conversion (mol.%) 1.2 n.d. 0.3 7.5 Sel. Acetone (mol.%) 2.5 1.9 4.7 7.6 Sel. Methanol (mol.%) 0.5 0.2 0.5 1.0 Sel. TBA (mol.%) 88.4 92.1 90.6 88.1 Sel. DTBP (mol.%) 9.1 6.0 4.7 4.3 Composition Isobutane 57.704 56.992 59.018 57.534 53.360 MEOH/MF 0.101 0.108 0.110 0.131 0.163 Acetone 1.128 1.191 1.265 1.605 1.988 TBA 21.338 25.640 30.712 36.183 41.556 DTBP 0.681 0.971 1.237 1.291 1.285 TBHP 18.084 14.165 6.709 2.198 0.631 CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL RUN A 9 10 11 Catalyst .2% Pd, .08% Au on Al 2 O 3 Catalyst (cc) 100 100 100 Pressure (MPa) 2.1 2.1 2.1 Feed Rate (cc/Hr.) 100 100 100 Temperature (°C) 60 80 100 Time on Stream (Hr) 4 4 4 Space Vel. (cc/cc) 1.0 1.0 1.0 TBHP Conversion (mol.%) 56.0 83.2 95.7 IB Conversion (mol.%) n.d. 11.0 12.9 Sel. Acetone (mol.%) 1.6 6.9 11.3 Sel. Methanol (mol.%) 0.1 4.7 6.1 Sel. TBA (mol.%) 93.0 88.0 85.2 Sel. DTBP (mol.%) 5.4 5.0 3.5 Composition Isobutane 57.704 60.017 51.337 50.249 MEOH/MF 0.101 0.106 0.351 0.477 Acetone 1.128 1.232 1.801 2.386 TBA 21.338 28.601 40.571 43.475 DTBP 0.681 1.121 1.292 1.172 TBHP 18.084 7.959 3.039 0.773 CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL RUN A 12 13 14 Catalyst .2% Pd, .08% Au on Al 2 O 3 Catalyst (cc) 100 100 100 Pressure (MPa) 2.1 2.1 2.1 Feed Rate (cc/Hr.) 200 200 200 Temperature (°C) 60 80 100 Time on Stream (Hr) 4 4 4 Space Vel. (cc/cc) 2.0 2.0 2.0 TBHP Conversion (mol.%) 22.6 67.9 92.4 IB Conversion (mol.%) 6.1 16.7 16.9 Sel. Acetone (mol.%) 5.2 9.1 15.7 Sel. Methanol (mol.%) 1.3 1.4 2.9 Sel. TBA (mol.%) 84.1 83.2 79.5 Sel. DTBP (mol.%) 10.7 7.7 4.8 Composition Isobutane 57.704 54.157 48.039 47.959 MEOH/MF 0.101 0.120 0.163 0.273 Acetone 1.128 1.264 1.849 2.821 TBA 21.338 28.374 41.215 44.881 DTBP 0.681 1.036 1.443 1.327 TBHP 18.084 13.996 5.799 1.383 CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL RUN B 15 16 17 18 Catalyst .2% Pd, .08% Au on Al 2 O 3 Catalyst (cc) 50 50 50 50 Pressure (MPa) 3.5 3.5 3.5 3.5 Feed Rate (cc/Hr.) 25 25 25 25 Temperature (°C) 80 100 120 140 Time on Stream (Hr) 4 4 4 4 Space Vel. (cc/cc) 0.5 0.5 0.5 0.5 TBHP Conversion (mol.%) 88.9 93.2 96.2 97.4 Selectivity IC4= (mol.%) 0.0 -0.0 0.0 0.1 Sel. Acetone (mol.%) 9.7 11.6 13.9 14.0 Sel. Methanol (mol.%) 1.9 2.6 3.3 2.9 Sel. TBA (mol.%) 82.8 83.3 81.6 82.0 Sel. DTBP (mol.%) 7.5 5.1 4.4 4.0 Remarks H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis Composition IC4= 0.001 0.001 0.000 0.002 0.007 MEOH/MF 0.016 0.128 0.183 0.229 0.208 Acetone 0.008 1.072 1.347 1.662 1.692 TBA 79.968 94.807 95.467 95.799 96.080 DTBP 0.055 1.085 0.787 0.718 0.663 TBHP 19.146 2.126 1.293 0.731 0.506 CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL RUN B 19 20 21 22 Catalyst .2% Pd, .08% Au on Al 2 O 3 Catalyst (cc) 50 50 50 50 Pressure (MPa) 3.5 3.5 3.5 3.5 Feed Rate (cc/Hr.) 50 50 50 50 Temperature (°C) 80 100 120 140 Time on Stream (Hr) 4 4 4 4 Space Vel. (cc/cc) 1.0 1.0 1.0 1.0 TBHP Conversion (mol.%) 78.0 88.7 93.6 97.0 Selectivity IC4= (mol.%) -0.0 0.0 0.0 0.1 Sel. Acetone (mol.%) 9.6 14.9 18.4 20.4 Sel. Methanol (mol.%) 1.6 3.2 4.7 5.9 Sel. TBA (mol.%) 83.0 80.3 78.1 77.0 Sel. DTBP (mol.%) 7.4 4.7 3.5 2.7 Remarks H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis Composition IC4= 0.001 0.000 0.001 0.002 0.010 MEOH/MF 0.016 0.103 0.212 0.317 0.404 Acetone 0.008 0.933 1.643 2.135 2.446 TBA 79.968 92.570 94.177 94.745 95.098 DTBP 0.055 0.952 0.706 0.560 0.457 TBHP 19.146 4.213 2.155 1.233 0.573 CATALYTIC CONVERSION OF TERT-BUTYLHYDROPEROXIDE TO TERT-BUTYLALCOHOL RUN A 23 24 25 26 Catalyst .2% Pd, .08% Au on Al 2 O 3 Catalyst (cc) 50 50 50 50 Pressure (MPa) 3.5 3.5 3.5 3.5 Feed Rate (cc/Hr.) 100 100 100 100 Temperature (°C) 80 100 120 140 Time on Stream (Hr) 4 4 4 4 Space Vel. (cc/cc) 2.0 2.0 2.0 2.0 TBHP Conversion (mol.%) 45.0 85.7 94.5 96.9 Selectivity IC4= (mol.%) -0.0 0.0 0.0 0.1 Sel. Acetone (mol.%) 7.5 15.7 22.5 24.1 Sel. Methanol (mol.%) 1.2 3.9 6.9 7.9 Sel. TBA (mol.%) 82.9 79.9 74.8 73.7 Sel. DTBP (mol.%) 9.6 4.4 2.7 2.1 Remarks H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis H 2 O Free Basis Composition IC4= 0.001 0.000 0.001 0.006 0.013 MEOH/MF 0.016 0.053 0.245 0.461 0.539 Acetone 0.008 0.424 1.663 2.626 2.894 TBA 79.968 87.174 93.373 94.467 94.655 DTBP 0.055 0.726 0.644 0.458 0.376 TBHP 19.146 10.532 2.743 1.052 0.602

Claims: A method for the decomposition of tertiary butyl hydroperoxide to tertiary butyl alcohol, wherein a tertiary butyl hydroperoxide charge stock comprising an Organic solvent solution of tertiary butyl hydroperoxide that contains from 5 to 30 wt.% of tertiary butyl hydroperoxide is brought into continuous contact with a catalytically effective amount of hydroperoxide decomposition catalyst Consisting of alumina having deposited thereon 0.2 wt.% palladium and 0.08 wt.% of gold in a hydroperoxide decomposition reaction zone and liquid phase with agitation under hydroperoxide conversion conditions including the temperature within the range of 25° to 250°C, a space velocity of 0.5 to 2 volumes of tertiary butyl hydroperoxide charge stock per volume of catalyst per hour and a pressure of 0.1 to 7.0 MPa (0 to 1,000 psig) to convert said tertiary butyl hydroperoxide to decomposition products, principally tertiary butyl alcohol, wherein said tertiary butyl hydroperoxide charge stock comprises a solution of tertiary butyl hydroperoxide in a cosolvent mixture of 50 to 80 wt.% of isobutane with, correspondingly, 50 to 20 wt.% of tertiary butyl alcohol. A method as claimed in claim 1, wherein the temperature is in the range of 40° to 150°C, the space velocity is within the range of 0.5 to 1 volumes of tertiary butyl hydroperoxide charge stock per volume of catalyst per hour and the pressure is 0.1 MPa.

Inventors: MUELLER MARK ALLAN, SANDERSON JOHN RONALD, SHEU YU-HWA EDWARD, MUELLER, MARK ALLAN, SANDERSON, JOHN RONALD, SHEU, YU-HWA EDWARD
Applicants: HUNTSMAN SPEC CHEM CORP, HUNTSMAN SPECIALTY CHEMICALS CORPORATION
Application year: 1994
Main classification: C07C29
IPC codes: C07C31, C07C27, C07B61, C07C29, B01J23